Spinal Confusion

...an attempt to clarify confusing and innacurate information in science articles

Friday, March 24, 2006

Nuclear Reprogramming

Gee, you wait a few hours and someone beats you to the punch.

Rebecca over at Mary Meets Dolly blogged about a Technology Review article out today entitled Nuclear Reprogramming. She knows her stuff, so give her a read and then come back.

Allrighty then. So you now have some idea about what's being proposed. Essentially, deriving embryonic stem cells without creating or destroying an embryo. The Holy Grail, if you will.

All these weird terms are thrown out at you -- Cdx2, Nanog, ANT, PGD -- and I plan on skipping those today. Because, really, they're just clutter.

Today, we're going to discuss cell biology and, hopefully, we're going to do so in a way that a fifth grader can understand. So, please, forget everything you know about a cell for the duration of this entry. When you're done, you'll thank me.

Biology Made Easy

If you ask someone what a cell is, you'll get different answers from different people.

Gaming enthusiasts will delight you with tales of the new processor powering the PlayStation 3. Stephen King fans will reminisce of the bars that could not contain Andy Dufresne in The Shawshank Redemption. Those who have sat through a biology class will tell you that a cell is the basic unit of life.

They would all be right. I'm going to offer you a different definition.

A cell is a component of life that contains a nucleus and cytoplasm, and organelles that help it function. A cell's functioned is defined primarily by two things: the genes expressed in its nucleus, and the proteins floating around in the cell.

Lower estimates put the number of genes in the human body right around 25,000. This makes the number of unique genetic expression profiles almost impossible to consider. It gets even more complicated, but we're going to keep things simple and say that there are only 4 genes -- A, B, C, and D.

Each of these genes can be expressed -- turned on -- or not -- turned off -- giving us 16 distinct genetic profiles. (A, AB, ABC, ABCD, ABD, AC, ACD, AD, B, BC, BCD, BD, C, CD, D, [none])

Each of these profiles will cause the cell to perform a different function. AB, as an example, would function as a zygote; ABC an embryonic stem cell; ACD a neural stem cell; AD a neuron; and so on and so forth.

I hope you're still with me, because here's the cool part -- scientists can add and delete genes in the laboratory. Say CD is a skin cell. By adding the A gene, the cell would become a neural stem cell. By deleting C from this neural stem cell, the cell becomes a neuron.

More interestingly, scientists could take a skin cell (CD), delete the D, add an A and a B and -- bingo! -- an embryonic stem cell (ABC). All without creating an embryo.

That's the power of nuclear reprogramming. This is the future of science.

This is the stuff that makes me drool.